Welcome to DroneRacingPilots!
Join our free drone racing community today!
Sign up

Antenna Decisions

coyote_dc5

Well-Known Member
Joined
Jun 22, 2020
Messages
152
Reaction score
102
Age
39
So I have a green hornet which came with a stubby RHCP omni and I have two spare omni RHCP SMA antennas all capable of different gain ratings.

My questions are

- which way round the higher gains should be used i.e on goggles or quad
- should the gain be matched like the circular polarization or doesn't this matter?
- is it good practice to match the number of leaves in the corresponding rx and tx antennas

The three RHCP antennas I have are as follows, so just looking for advise on which ones to place where for best results

iFlight stubby 5dbi
TBS Triumph 1.26 dbic (what dbi does this translate to?)
Eachine cloverleaf 5dbi
 
Last edited:

coyote_dc5

Well-Known Member
Joined
Jun 22, 2020
Messages
152
Reaction score
102
Age
39
The reason I post is because I've been experiencing noise in my OSD. There is a little video below showing this.


Any help would be appreciated.

Some pics of the setup as well.
PXL_20201001_141618569.jpg

PXL_20201001_141610757.jpg
 
Last edited:

Earthman

Member
Joined
Aug 18, 2019
Messages
18
Reaction score
12
An Omni antenna, like the simple rod antennas, transmits and receives about same in all directions except off the ends on the antenna where there are dead zones. So, don’t point the receiver antenna at the transmitter antenna or vice versa.

Also, rod antennas polarize the transmit and receive signals such that vertical antennas are vertically polarized and horizontal antennas are horizontally polarized. Therefore, keep the transmit and receive antennas parallel for best results.

An antenna with gain flattens or focuses the transmit and/or receive signal patterns; i.e., they squeeze the available radio energy into a tighter pattern. So, higher gain antennas tend to be directional. They work better in one direction but not as well or at all in other directions. Low-gain antennas are more forgiving in this respect. High-gain antennas are not necessarily better.

A patch antenna is directional. The transmitter needs to be in a direction perpendicular to the plane of the receive antenna for best results.

Clover leaf and patch antennas are circularly polarized. They can be made to have clockwise or counterclockwise polarization.

in any case, match the type, polarization, and orientation of the transmit and receive antennas for best results. If you tend to fly all around you, low-gain vertically polarized rod transmit and receive antennas may be best (never point the antennas at the quad). If you can keep the UAV out in front of you, antennas with some gain/direction may be best.

The above is based on ideal conditions. In the real world, antennas also pick up reflected signals and radio signals are polarized by reflecting surfaces, so even mismatched antennas can work to some degree. Still, you should get better results if you match the antennas, etc.

Finally, 2.4 and 5.8 MHz radio frequencies are short wave lengths that travel in straight lines, i.e., they are line of sight except for reflected signals. And just like light, these high radio frequencies are attenuated by just about everything (buildings, hills, trees, people, etc.). If you can’t see through it, neither can the radio equipment you are using to control your aircraft. Any signals that get through or around attenuating stuff are reflected, depolarized, weaker signals.

All of the stuff mentioned above are what cause signal loss/“interference.” If you fly analog equipment, get used to it, it’s not going away. Digital equipment can reduce but not eliminate the problem.
 

Latest threads

Members online

Forum statistics

Threads
3,514
Messages
29,973
Members
2,954
Latest member
ABSURDFPV